VVT fault. Aways in advance position.
#1
09-19-2009, 10:58 AM
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Posts: n/a
VVT fault. Aways in advance position.
After narrowing down various problems with a 4.0 V8 S-type I bought - it seems that the VVT is ALWAYS in the timing 'advance' position.
ie. Severe lack of power at lower revs - then at 2500-3000rpm - takes off like it should.
NO fault light, NO fault codes even with the leads pulled off the solenoids - and no return to the default 'retarded timing'.
Now for BOTH banks to be stuck like that looks like 'somebody' has been tampering and jammed the solenoids / VVT in position...and somehow deactivated the fault code...
This usually raises a 'hmmmm...' and a shrug of the shoulders from mechanics.
I decided NOT to go for the usual engine flush treatment as the chances of BOTH banks jamming is so remote so as to be farcical, and the fact that it raises no fault codes - connectors on or off is a real head scratcher.
So - suggestions please if you've heard of this before.
Engine runs fine (albeit a little rich - but still OK) at sub 3000 revs.
ie. Severe lack of power at lower revs - then at 2500-3000rpm - takes off like it should.
NO fault light, NO fault codes even with the leads pulled off the solenoids - and no return to the default 'retarded timing'.
Now for BOTH banks to be stuck like that looks like 'somebody' has been tampering and jammed the solenoids / VVT in position...and somehow deactivated the fault code...
This usually raises a 'hmmmm...' and a shrug of the shoulders from mechanics.
I decided NOT to go for the usual engine flush treatment as the chances of BOTH banks jamming is so remote so as to be farcical, and the fact that it raises no fault codes - connectors on or off is a real head scratcher.
So - suggestions please if you've heard of this before.
Engine runs fine (albeit a little rich - but still OK) at sub 3000 revs.
#2
09-19-2009, 11:54 AM
Veteran Member
What codes would you expect?
I can't see how any could be deactivated.
What are the fuel trims like at idle and at (say) 2000 rpm? What are the O2 waveforms like at those rpms? Is it running closed loop on both banks at those rpms?
How rich and how do you know?
Have all the readiness monitors completed?
Could you have a wiring harness fault?
Do the solenoids share anything electrical (apart from PCM) such as grounds or power feed?
I can't see how any could be deactivated.
What are the fuel trims like at idle and at (say) 2000 rpm? What are the O2 waveforms like at those rpms? Is it running closed loop on both banks at those rpms?
How rich and how do you know?
Have all the readiness monitors completed?
Could you have a wiring harness fault?
Do the solenoids share anything electrical (apart from PCM) such as grounds or power feed?
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